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Queen’s University project feature P.L. Light systems

"New LEDs have greatly improved light uniformity over our crops"

An integrated driver and high efficiencies were two of the top reasons Queen’s University chose to retrofit their research greenhouses with the HortiLED Top 2.0. The Queen’s University Phytotron was designed and built in 1996 as a center for experimental plant biology research. The facility has a combination of 26 growth chambers and six greenhouse compartments to provide a diverse array of environments for the growth of experimental plants and organisms. The Phytotron greenhouses had not been upgraded for many years, and they had been using legacy magnetic ballast HPS luminaires to light their crops. When Saeid Mobini, the University’s Phytotron Manager, took over a year ago he knew how important having a good lighting system was to the health and productivity of the plants. With the 2020 pandemic bringing activity to a halt in the research greenhouses, it provided them the perfect opportunity to upgrade their lighting system.

Saeid Mobini

Professional experience
With an extensive background in horticulture and having worked as a greenhouse specialist for the Government of Alberta, Saeid Mobini has spent the last 12 years providing consulting services to the Canadian horticultural industry before joining Queen’s University in 2020. Through his professional experience, he has had the opportunity to evaluate and compare 22 different LED horticultural luminaires and worked with several LED manufacturers around North America, Europe, and Asia. He has also designed lighting plans for high wire crops, greenhouse ornamentals, and leafy greens, as well as vertical farms. Having had the opportunity to work with so many different LEDs, when it came to choosing a system that worked for the Queen’s greenhouses, he elected to go with P.L. Light Systems’ HortiLED Top 2.0 Daylight Spectrum, as it ranked in the top-performing LEDs out of the 22 lights he had trialed.

Some reasons for going with the HortiLED Top 2.0 included that it has high efficacy, which allowed them to receive the maximum rebate amount. Besides, it has an integrated driver (vs. external driver box), making it easy to install with minimum wiring and it has a very stable spectrum for plant growth. Finally, P.L. has a knowledgeable sales and customer care team with excellent warranty support.

No external driver box
Having no external driver box was a very important point he stressed, when choosing a luminaire and is something he advises his greenhouse clients on when choosing an LED system. "This is because when a luminaire has an external driver, it involves higher labor costs and more wiring - it also means if you need to move the lights for some reason, it becomes more costly and complicated.  Having an integrated driver, therefore, saves the grower time and money," he said.

With the new HortiLED Top 2.0 luminaires installed, the team has seen significant improvements in plant quality. The University has a variety of different projects they are working on, including plant phenotyping, screening, crossing, hydroponics, and aquaponics (vegetables and leafy greens), as well as field crops, and their conservatory—which is a collection of over 250 different tropical trees, flowers, and air plants—all of which are now grown under HortiLED Top 2.0 Daylight luminaires.

The new LEDs have also greatly improved the light uniformity over the crops. Previously, the old magnetic ballast luminaires had poor uniformity and high peaks of wavelengths in the 820nm range, which put a lot of heat stress on the various crops they were growing. With the HortiLED Top 2.0, the uniformity is greatly improved, and the spectrum is also more tuned to what the plants need. Having high light uniformity is very important for crop growth, as you can have areas of high and low intensity which will adversely affect plant health.  Working with a customized light plan, as well as luminaires that provide a broad output helps make sure that there are no “hot” or “cold” areas in the greenhouse, ensuring all plants are receiving the same amount of light and therefore have uniform growth.  

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